Panthers' investments paying dividends

While no single player may be as important to a defense as a shutdown corner such as Denver's Champ Bailey, no defensive position is more important than the line. Why? Strong play up front goes a long way toward hiding weaknesses in the back seven.

It also gives defensive coordinators a lot more freedom in their play-calling. Coordinators who have a defensive line that can stop the run don't have to walk their safeties up to the line of scrimmage nearly as often, making the defense less vulnerable to play-action. If the line consistently has success rushing the passer, the coordinator can drop seven men into coverage and force opposing quarterbacks to throw into tight spaces while under pressure.

Several defensive lines do one or the other well, but few excel at defending both the run and the pass. Below is a list of the top-five defensive lines in the league. They can force offenses into obvious passing downs by shutting down the run and they have the playmakers to take advantage of those situations by getting to the quarterback.

While talent is important, the personnel must fit the scheme so that talent reaches its full potential. For example, Atlanta last year ran a 3-4-defense that didn't take advantage of the ability of DEs Patrick Kerney and Brady Smith to make plays in the backfield. Now that the Falcons are running an aggressive, one-gap 4-3 scheme, both players should be more productive.

So, which NFL teams have the best defensive lines? Our list starts with the Carolina Panthers: